SWAG��Ƶ

Scientists can tell the age of a tree by counting the number of rings inside or on a stump. John Mohan, Ph.D., assistant professor of Marine Sciences, can learn a lot more by looking at the rings inside fish.

“Little bio minerals, that are part of their hearing organ, lay down rings kind of like tree rings that are useful for age, but looking at these growth bands and looking at the chemical composition of them can also tell you something about their movement,” he explained. “It turns out to be a really good way to basically look at the entire life of a fish and try to understand what habitats it was in.”

Mohan is the newest faculty member in the School of Marine and Environmental Programs. He arrives at SWAG��Ƶ from Texas A&M University at Galveston, where he has been for the last five years as postdoctoral researcher and an assistant research scientist. 

“As a research scientist, I was allowed to be a principal investigator on projects,” he commented. “I could write my own proposals and get funding to basically run my own research projects. I consider myself a fish ecologist. I'm mostly interested in movement patterns, habitat use, and feeding behaviors of fishes.”

Mohan has a keen interest in sharks and their movements.

“When I started working off the coast of Galveston with recreational charter fishermen, we studied how those fishermen handle sharks when they capture them and then check the survival rates when they release the animals,” he said. “Survival is a very important parameter in models that are used to assess populations. So, managers really need to know that data.”

Shark sightings off the coast of Maine have been increasing in recent years. This summer Maine experienced its first shark fatality when a swimmer was attacked off Bailey Island.

“The shark populations in Maine have been growing because their prey sources are growing,” Mohan stated. “I believe we will be seeing more human-shark interactions.”

Mohan says he is more than happy to work in collaboration with state marine officials and other researchers tracking the movements of sharks in Maine waters.

“I have always been very collaborative in my research approach and I think today that's what it takes to be successful,” he said. “You have to work together. I definitely am willing to collaborate with those researchers and assist any way I can.”

He is also interested in reaching out to local fishermen, much like he did in Galveston.

“A lot of the work that I did in the Gulf of Mexico involved citizen scientists and that is something that I'm really interested in trying to build here,” he stated. “Whether that is just having them report a sighting of some sort or working on projects with recreational anglers. Citizens care just as much as scientists do about the fish populations around here.”

Since he grew up in Pennsylvania, Mohan is used to cold temperatures and snow. He says has no concerns about moving from the warm climate of Texas to Maine. However, he says it is a bit unnerving starting a new position, in a new place, in the middle of a pandemic.

“Right after I accepted the position the pandemic hit,” he said. “So, it definitely creates challenges. That being said, I think that we are in a unique position to overcome those challenges because of the planning that has been done and the community atmosphere of everyone understanding that we are in this together. It is not a long-term issue, so it will be all about getting students out into the field, getting them in the lab, and getting their hands on fish.”